USB-2416
USB-based 24-bit, Isolated, High-Channel-Count Multifunction DAQ Device
User's Guide
December 2019. Rev 9
© Measurement Computing Corporation
2
HM USB-2416.docx
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for more information about Measurement Computing trademarks.
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photocopying, recording, or otherwise without the prior written permission of Measurement Computing
Corporation.
Notice
Measurement Computing Corporation does not authorize any Measurement Computing Corporation product for
use in life support systems and/or devices without prior written consent from Measurement Computing
Corporation. Life support devices/systems are devices or systems that, a) are intended for surgical implantation
into the body, or b) support or sustain life and whose failure to perform can be reasonably expected to result in
injury. Measurement Computing Corporation products are not designed with the components required, and are
not subject to the testing required to ensure a level of reliability suitable for the treatment and diagnosis of
people.
3
Table of Contents
Preface
About this User's Guide ....................................................................................................................... 5
What you will learn from this user's guide ......................................................................................................... 5
Conventions in this user's guide ......................................................................................................................... 5
Where to find more information ......................................................................................................................... 5
Chapter 1
Introducing the USB-2416 .................................................................................................................... 6
Functional block diagram ................................................................................................................................... 6
Chapter 2
Installing the USB-2416 ........................................................................................................................ 7
Unpacking........................................................................................................................................................... 7
Installing the software ........................................................................................................................................ 7
Connecting the external power supply ................................................................................................................ 7
Installing the hardware ....................................................................................................................................... 7
Optional components .......................................................................................................................................... 7
AI-EXP32 ......................................................................................................................................................................... 7
ACC-202 Din-rail kit ........................................................................................................................................................ 7
Connecting an AI-EXP32 to the DSUB37 expansion connector ........................................................................ 8
Configuring the hardware ................................................................................................................................... 8
Calibrating the hardware..................................................................................................................................... 8
Factory calibration ............................................................................................................................................................ 8
Field calibration ................................................................................................................................................................ 9
Updating firmware .............................................................................................................................................. 9
Chapter 3
Functional Details ............................................................................................................................... 10
External components ........................................................................................................................................ 10
Screw terminals................................................................................................................................................................10
LEDs ................................................................................................................................................................................13
USB connector .................................................................................................................................................................14
External power connector ................................................................................................................................................14
37-pin DSUB expansion connector ..................................................................................................................................14
Analog input mode ...........................................................................................................................................................14
Thermocouple inputs .......................................................................................................................................................15
Noise filtering, data rate, and throughput rate ..................................................................................................................16
Multiple-channel throughput rates ...................................................................................................................................16
Input isolation ................................................................................................................................................... 17
Digital I/O ......................................................................................................................................................... 18
Internal pull-up/pull-down capability...............................................................................................................................18
External pull-up/pull-down capability .............................................................................................................................19
Counter input terminals (CTR0, CTR1) ........................................................................................................... 20
USB-2416 mechanical drawings ...................................................................................................................... 20
Chapter 4
Specifications ...................................................................................................................................... 21
Analog input ..................................................................................................................................................... 21
Channel configurations ..................................................................................................................................... 22
Compatible sensors ..........................................................................................................................................................22
Accuracy ........................................................................................................................................................... 22
Thermocouple measurement accuracy .............................................................................................................................22
Analog input DC voltage measurement accuracy: ...........................................................................................................31
Input bandwidth ...............................................................................................................................................................33
USB-2416 User's Guide
4
Noise performance ...........................................................................................................................................................33
Channel switching error ...................................................................................................................................................34
Throughput rate ................................................................................................................................................ 35
Analog input calibration ................................................................................................................................... 36
Digital input/output........................................................................................................................................... 36
Counter ............................................................................................................................................................. 37
Memory ............................................................................................................................................................ 37
Microcontroller ................................................................................................................................................. 37
Power ................................................................................................................................................................ 38
USB specifications ........................................................................................................................................... 38
Environmental .................................................................................................................................................. 38
Mechanical ....................................................................................................................................................... 38
Screw terminal connector type and pinout ....................................................................................................... 39
Screw terminal pinout ......................................................................................................................................................39
Optional AI-EXP32 expansion module ............................................................................................................ 42
AI-EXP32 Screw terminal pinout ....................................................................................................................................44
USB-2416 screw terminal pinout (with AI-EXP32 attached) ..........................................................................................46
EU Declaration of Conformity ............................................................................................................ 47
5
Preface
About this User's Guide
What you will learn from this user's guide
This user's guide describes the Measurement Computing USB-2416 data acquisition device and lists device
specifications.
Conventions in this user's guide
For more information
Text presented in a box signifies additional information and helpful hints related to the subject matter you are
reading.
Caution! Shaded caution statements present information to help you avoid injuring yourself and others,
damaging your hardware, or losing your data.
Bold text is used for the names of objects on a screen, such as buttons, text boxes, and checkboxes.
Italic text is used for the names of manuals and help topic titles, and to emphasize a word or phrase.
Where to find more information
Additional information about the USB-2416 is available on our website at www.mccdaq.com. You can also
contact Measurement Computing Corporation by phone, fax, or email with specific questions.
Knowledgebase: kb.mccdaq.com
Tech support form: www.mccdaq.com/support/support_form.aspx
Email: techsupport@mccdaq.com
Phone: 508-946-5100 and follow the instructions for reaching Tech Support
For international customers, contact your local distributor. Refer to the International Distributors section on our
website at www.mccdaq.com/International
.
6
Chapter 1
Introducing the USB-2416
The USB-2416 is a USB multifunction measurement and control device that provides the following features:
16 differential (DIFF) or 32 single-ended (SE) analog inputs with 24-bit resolution and sample rates up to
1 kS/s
o Each channel is software selectable as SE or DIFF; you lose one SE channel for each DIFF channel
pair
o 16 analog inputs can be configured as differential thermocouple (TC) inputs; includes built-in cold-
junction compensation and open thermocouple detection
o Add up to 32 SE/16 DIFF channels by connecting the USB-2416 to an AI-EXP32 expansion module
software-selectable analog input ranges of ±20 V, ±10 V, ±5 V, ±2.5 V, ±1.25 V, ±0.625 V, ±0.312 V,
±0.156 V, and ±0.078 V.
A minimum of 500 VDC input isolation between field wiring and the USB interface.
Eight digital I/O lines and two 32-bit counters, which can be expanded to 24 DIO channels by connecting
the USB-2416 to an AI-EXP32 expansion module.
Six banks of removable screw-terminal blocks provide connectivity to the analog input channels, digital I/O
lines, and counter/timer channels.
The USB-2416 is powered by an external 5 V, 2 A regulated power supply (PS-5V2AEPS) that ships with the
device.
Functional block diagram
USB-2416 functions are illustrated in the block diagram shown here.
Figure 1. Functional block diagram
7
Chapter 2
Installing the USB-2416
Unpacking
As with any electronic device, you should take care while handling to avoid damage from static
electricity. Before removing the device from its packaging, ground yourself using a wrist strap or by simply
touching the computer chassis or other grounded object to eliminate any stored static charge.
Contact us immediately if any components are missing or damaged.
Installing the software
Refer to the MCC DAQ Quick Start and the USB-2416 product page on our website for information about the
software that supports the device.
Install the software before you install your device
The driver needed to run the USB-2416 is installed with the software. Therefore, you need to install the
software package you plan to use before you install the hardware.
Connecting the external power supply
Power to the USB-2416 is provided with the 5 V external power adapter (PS-5V2AEPS). Connect the adapter
cord to the power connector on the USB-2416, and plug the AC adapter into an electrical outlet.
Refer to Figure 4 on page 10 for the location of the
Power LED.
Installing the hardware
Connect the USB-2416 using the cable provided to a USB port on a computer running Windows. Windows
finds and installs the device driver automatically, and notifies you that the device is ready to use.
Caution! To avoid losing data and/or communication with the USB-2416, do not disconnect the USB cable
while the USB LED is on.
If the Activity LED turns off
If the Activity LED turns on but then turns off, the computer has lost communication with the USB-2416. To
restore communication, disconnect the USB cable from the computer, and then reconnect it. This should restore
communication, and the Activity LED should turn back on.
Optional components
AI-EXP32
The AI-EXP32 analog input expansion device adds up to 16 differential or 32 single-ended inputs.
ACC-202 Din-rail kit
Use the ACC-202 accessory for mounting a USB-2416 to a standard DIN rail.
The thread-forming screws attach the DIN rail clip to your device.
Two ACC-202 kits are required to mount both the USB-2416 and the
AI-EXP32 to a DIN rail.
Thread-forming
screws
USB-2416 User's Guide Installing the USB-2416
8
Connecting an AI-EXP32 to the DSUB37 expansion connector
Use the 37-pin expansion connector to connect the USB-2416 to an AI-EXP32 expansion module.
To connect the two devices directly to each other, complete the following steps:
1. Disconnect the USB cable from the USB-2416.
2. Remove the external power cable from the USB-2416.
3. Connect the two devices together by inserting the AI-EXP32 male DSUB37 connector into the female
DSUB37 connector on the USB-2416.
Figure 2. USB-2416 directly connected to an AI-EXP32
4. Turn the connected devices over and secure the connection by screwing the connection plate to both
devices, as shown below.
Figure 3. USB-2416 secured to an AI-EXP32
5. Connect the external power supply to the power input port of the USB-2416, and then plug it into an
AC outlet.
6. Connect the USB cable from the USB-2416 to the host computer USB port.
Connect to a USB 2.0 high-speed hub to achieve the highest transfer rate (480 Mbps). When connected to a
USB 1.1 full-speed port, the transfer rate is limited to 12 Mbps.
Configuring the hardware
Except for the DIO pull-up selection, all hardware configuration options on the USB-2416 are software
controlled. You can select some of the configuration options using InstaCal, such as the analog input
configuration (single-ended or differential channels). When measuring from thermocouples, make sure you
configure the channels for differential mode.
Caution! Turn off power to all devices connected to the system before making connections. Electrical shock
or damage to equipment can result even under low-voltage conditions.
Information on signal connections
General information regarding signal connection and configuration is available in the Guide to DAQ Signal
Connections on our website at www.mccdaq.com/support/DAQ-Signal-Connections.aspx.
Calibrating the hardware
Factory calibration
The Measurement Computing Manufacturing Test department performs the initial factory calibration. Return
the device to Measurement Computing Corporation when calibration is required. The recommended calibration
interval is one year.
USB-2416 User's Guide Installing the USB-2416
9
Field calibration
The USB-2416 supports field calibration. Calibrate the device using InstaCal whenever the ambient temperature
changes by more than ±10 °C from the last calibration.
Caution! Always handle components carefully, and never touch connector terminals or circuit components
unless you are following ESD guidelines in an appropriate ESD-controlled area. These guidelines
include using properly-grounded mats and wrist straps, ESD bags and cartons, and related
procedures.
Avoid touching board surfaces and onboard components. Only handle boards by their edges. Make
sure the USB-2416 does not come into contact with foreign elements such as oils, water, and
industrial particulate.
The discharge of static electricity can damage some electronic components. Semiconductor
devices are especially susceptible to ESD damage.
Updating firmware
Your DAQ device contains firmware that can be updated in the field if required. Firmware is available for
download at www.mccdaq.com/firmware.aspx
. MCC recommends that you check this page periodically to see
if an update to your device firmware is available.
10
Chapter 3
Functional Details
External components
The USB-2416 components are shown in Figure 4.
Figure 4. USB-2416 components
1
Screw terminals (removable) for analog/TC
input and counter inputs
4
External power connector
2
Power (top) and Activity (bottom) LEDs
5
Screw terminals (removable) for
analog/TC input and counter input
3 USB connector 6 37-pin DSUB expansion connector
(connects to AI-EXP32)
Screw terminals
The USB-2416 has six groups of screw terminals—three on each side of the enclosure – that provide the
following connections:
16 analog/TC inputs (
CH0H/CH0L to CH15H/CH15L)
Eight digital I/O (
DIO0 to DIO7)
Two event counter inputs (
CTR0, CTR1)
One power output (
+VO)
Nine analog grounds (
GND)
Two digital grounds (
DGND)
Use 16 AWG to 30 AWG wire when making connections to the screw terminals. Connectors are identified in
Figure 5 through Figure 7 on pages 11-13.
USB-2416 User's Guide Functional Details
11
Figure 5. 16-channel differential mode pinout
Differential connection guidelines
When connecting differential voltage inputs to a floating voltage source, make sure there is a DC return path
from each voltage input to ground. You make this path by connecting a resistor from each input to a GND pin.
A value of approximately 100 kΩ can be used for most applications.
Leave unused input channels either floating or tied to GND.
Source impedances should be kept as small as possible to avoid settling time and accuracy errors.
When configuring thermocouple sensors, keep any stray capacitance as small as possible relative to GND to
avoid settling time and accuracy errors. For thermocouple channels, do not provide a return path to ground. This
is done internally.
USB-2416 User's Guide Functional Details
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Figure 6. 32-channel single-ended mode pinout
USB-2416 User's Guide Functional Details
13
Figure 7. 32-channel single-ended mode pinout when connected to AI-EXP32
LEDs
When the USB-2416 is connected to a computer and in its normal idle state, both LEDs are lit solid green.
Power LED
The Power LED is the top LED on the right side of the USB-2416 housing.
The Power LED blinks when you plug the power supply into the USB-2416, and continues to blink while the
device is being initialized. If it continues blinking for more than ½ second, then there is a problem with the
USB-2416 and you should cycle the power.
If an application issues a blink LED command, then the power LED blinks a few times.
USB-2416 User's Guide Functional Details
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Activity LED
The (USB) Activity LED is the bottom LED on the right side of the USB-2416 housing. It blinks rapidly when
both the USB cable and external power cables are plugged in. It continues blinking rapidly while the device is
connecting to the computer, and then turns solid.
Whenever the device receives a USB command, the Activity LED blinks off and then returns to solid green.
When an analog in scan is running, the Activity LED blinks continuously.
USB connector
The USB connector is on the right side of the USB-2416 provides communication.
External power connector
The USB-2416 require external power through this connector to provide sufficient power for the USB-2416.
Connect the PS-5V2AEPS power supply to the external power supply connector. This power supply provides
5 VDC, 2 A power to the USB-2416.
37-pin DSUB expansion connector
The USB-2416 expansion connector is intended to connect directly to an AI-EXP32 expansion module. Do not
attempt to use any of the expansion port pins for any other purpose.
Power down the USB-2416 before connecting it to an AI-EXP32.
Figure 8. DSUB37 expansion connector pinout
Analog input mode
The USB-2416 makes high-resolution voltage measurements in either a single-ended or fully differential mode.
You can configure the USB-2416 for the following voltage input ranges.
±20 V
±10 V
±5 V
±2.5 V
±1.25 V
±0.625 V
±0.3125 V
±0.15625 V
±0.078125 V
Each analog input channel has the following measurement parameters:
signal type of volts or thermocouple type J, K, T, E, R, S, B, or N
full scale voltage from -20 to + 20 VDC
USB-2416 User's Guide Functional Details
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Thermocouple inputs
You can make up to 16 high-resolution differential thermocouple measurements with the USB-2416. Built-in
cold-junction sensors are provided for each of the screw-terminal blocks, and any supported TC type can be
attached to any of the 16 thermocouple channels.
Do not connect thermocouples as single-ended—doing so can cause false readings.
You do not need to use ground-referencing resistors because the analog front-end circuit level-shifts the
thermocouple's output into the common-mode input range of the A/D.
When configuring thermocouple sensors, keep any stray capacitance as small as possible relative to GND to
avoid settling time and accuracy errors.
The USB-2416 also provides an open thermocouple detection (OTD) feature for each of the analog input
channels configured for thermocouple measurement. This feature is automatically enabled as part of the overall
acquisition process, and detects if an open-circuit condition exists at the thermocouple sensor.
The USB-2416 provides electrostatic discharge (ESD) protection for each of the thermocouple inputs. However,
before handling thermocouple sensors, follow standard ESD practices and discharge any accumulated ESD
charge.
The USB-2416 includes an ESD protection device at each of the analog input terminal block pins. If an ESD or
transient voltage is coupled into the device, the input protection device(s) clamps the voltage to protect the
thermocouple input circuitry from possible damage.
Once the thermocouple sensor is connected to the USB-2416, the configuration options have been selected, and
the recommended 45 minute warm up has elapsed, the USB-2416 is ready to make high-resolution differential
voltage measurements.
Cold junction compensation (CJC) is needed to compensate for the additional thermal EMF's generated by
connecting the thermocouple leads to the USB-2416 terminal blocks.
CJC is performed using a high-resolution temperature sensor connected close to the USB-2416's terminal
blocks. The USB-2416 includes four separate CJC sensors—two on each side of the PCB. Software corrects for
the additional thermocouples created at the terminal.
Once the A/D and CJC data is collected, the application software uses this data to linearize to an accurate
temperature reading. The thermocouple linearization uses the latest NIST linearization coefficients for each of
the eight thermocouple types supported by the USB-2416.
Figure 9 below shows a typical thermocouple connection.
Figure 9. Differential thermocouple connection example
USB-2416 User's Guide Functional Details
16
Noise filtering, data rate, and throughput rate
Although the USB-2416 A/D converter has a maximum data rate of 3,750 S/s, the actual throughput rate you
observe for voltage and temperature data is determined by these formulas.
Maximum single
-channel throughput:
s
ratedata
µ
640
1
1
+
Maximum multiple
-
channel throughput:
∑
+
n
μs
640
rate
data
1
1
where n is the number of channels
See Table 18 and Table 19 in the Specifications chapter for details.
This drop-off in throughput rate is due to the USB-2416's noise filtering feature. You can control the amount of
the noise filtering by adjusting the data rate setting. By reducing the data rate, the averaging of samples
increases, and noise drops correspondingly.
Figure 10 illustrates this inverse relationship. This graph applies to the A/D converter only—do not expect this
level of performance from the USB-2416 itself.
Figure 10. USB-2416 A/D converter data rate vs. noise graph
If low noise is your main concern, you can operate the USB-2416 at very low data rates starting from 2.5 S/s. At
low rates, much of the noise is averaged out of the data, and issues such as reference noise become less
important.
At higher data rates, higher-frequency noise sources are not averaged out and begin to be troublesome. These
noise sources include the noise inherent in the A/D converter itself, which is not reducible.
Since thermocouples can pick up noise in your environment, select a data rate based on the primary noise
frequency. For example, to reduce the effect of 60 Hz noise, select a data rate of 60 (or a sub-multiple of 60,
such as 10 or 20).
Multiple-channel throughput rates
When setting different sample rates for different channels, be aware that the all channels will be sampled within
the same sample window based on the channel with the lowest sample rate.
For example, if you set a 10 Hz data rate for channel 0, and a 50 Hz data rate for channel 1, basically, both
channels pass the same number of samples per second to the host computer. However, more averaging is
performed on channel 0's samples; therefore, channel 0 is sampled at a higher resolution.
The USB-2416's A/D converter performs averaging, and the number of averages equals 30,000/data rate.
USB-2416 User's Guide Functional Details
17
In this example, channel 0 is sampled 3000 times over 100 ms, and all samples are averaged into one sample.
Then, channel 1 is sampled 600 times over 20 ms, and samples are likewise averaged into one sample.
The final samples are available to you at a maximum rate of about 8 Hz (8.245 Hz).
Figure 11. USB-2416 data rate vs. resolution example
Input isolation
The USB-2416 is an isolated data acquisition device. The analog input, digital I/O, counters, and all the digital
control/timing are referenced to an isolated ground as shown in the figure below. This ground is physically and
electrically separate from the ground use by the circuit connected to the system bus interface.
Isolation provides a barrier between the host computer and potentially hazardous voltages by physically and
electrically separating two parts of the measurement device.
The non-isolated ground is common to the chassis ground of the computer, while the isolated ground is not.
All analog measurements are made relative to the isolated ground. See Figure 12 for details.
Figure 12. USB-2416 input isolation diagram
When making measurements in industrial environments, DAQ devices can encounter hazardous voltages,
transients, large common mode voltages and fluctuating ground potentials. Any one of these issues can
seriously degrade the measurement accuracy of the device and possibly damage the measurement instrument.
To overcome these issues, some DAQ devices provide physical and electrical isolation. Some of the benefits of
isolation include:
Safety: A DAQ device employing physical and electrical isolation helps to keep high voltages and
transients from damaging the system-side host PC.
Ground loops: Improper grounding of the signal source that the DAQ device is measuring is one of the
most common sources of noise and measurement inaccuracies. Isolation improves the measurement
accuracy by physically preventing ground loops. Ground loops—a common source of noise and error—are
the results of a measurement system having multiple grounds at different potentials.
Common mode rejection: With isolation, a DAQ device can measure small signals in the presence of large
common mode voltages. Isolation increases the measurement system's ability to reject common mode
voltages. The common mode voltage is the signal that is common to both the positive and negative inputs
of the measurement device, but is not part of the signal to measure.
USB-2416 User's Guide Functional Details
18
Digital I/O
The USB-2416 provides up to eight digital I/O lines with read/write rates of 500 port reads or single bit reads
per second.
Digital input voltage ranges of 0 V to 15 V are permitted, with thresholds of 0.6 V (low) and 2.6 V (high). Each
DIO channel is an open-drain, which, when used as an output, is capable of sinking up to 150 mA for direct
drive applications. The maximum sink current is 150 mA per eight-channel bank, or if all eight channels are
used, 18 mA (maximum) per channel.
Figure 13 is an example of a typical DIO connection. The figure represents connections for one channel. The
other seven channels are connected in the same manner.
Figure 13. Digital output connection example
Internal pull-up/pull-down capability
Each of the eight DIO bits on the USB-2416 has a 47 kΩ pull-up/pull-down resistor. To configure these bits for
the 0 V pull-down option, you must open the USB-2416 case to access the three-pin jumper labeled JP1.
To open the case and set the JP1 jumper, do the following.
1. Turn over the USB-2416 and rest it on its top on a flat, stable surface.
2. Remove the five screws shown in Figure 14 from the bottom of the module.
3. Holding both the top and bottom sections of the module, turn it over, rest it on the surface, and carefully
remove the top portion of the case.
USB-2416 User's Guide Functional Details
19
Figure 14. Location of screws connecting bottom and top sections of case
Figure 15. Location and default configuration (pull-up) of JP1
The pull-up/pull-down voltage is common to all of the internal 47 kΩ resistors.
External pull-up/pull-down capability
You can also place an external pull-up resistor on any of the DIO bits. This enables you to pull the DIO bit up to
a voltage that exceeds the internal +5 V pull-up voltage.
When using external pull-up resistors, note the following:
You should either remove the JP1 jumper or store it by attaching it to one of the three pins.
When using external pull-up resistors, the internal resistors cause slight impedance shifts to digital lines in
the on state as the number of lines in the off state changes.
Figure 16. Digital I/O external resistor configuration
USB-2416 User's Guide Functional Details
20
Counter input terminals (CTR0, CTR1)
Two 32-bit event counters accept frequency inputs up to 1 MHz.
Refer to Figure 5 through Figure 7 on pages 11-13 for the location of these pins. The internal counter
increments when the TTL levels transition from low to high. The counter can count frequencies of up to 1 MHz.
USB-2416 mechanical drawings
Figure 17. Circuit board (top) and enclosure dimensions
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